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• Frequency Shifter - "Flashing Light Prize 2017"

  RoGeorge • 08/01/2017 at 01:35 • 2 comments

  This video is the one that was supposed to be the interesting one, but sent mostly as raw footage:

  The project is made of 2 identical motors, each with 4 magnets on top, and a reed switch nearby. The 2 magnetic reed switches are in series with a light bulb and a battery. The motors rotate the magnets they have on top of their axle producing a rotating magnetic field.
  

  When the motors are at the right distance from the switches, the reed contacts start to vibrate in the rhythm of the rotating magnetic field. Motors rotate very fast, probably around 2000 RPM.

  The trick is that each motor has a slightly different RPM. The reed switches are in series, so they emulate a logic AND for the bulb. Boolean AND is the same as multiplication. Multiplying RPM1 and RPM2 corresponding frequencies will produce two spectral components with the frequency RPM1 + RPM2 and RPM1 - RPM2, because cos(x)cos(y)=1/2[cos(x−y)+cos(x+y)]
  

  As a result, the bulb filament will see two frequencies, RPM1 + RPM2, and another frequency RPM1 - RPM2. Because the filament has thermal inertia, it will act as a low pass filter, and it will attenuate the component of frequency RPM1 + RPM2.

  On the contrary, RPM1 - RPM2 will be in the range of about 1 Hz, and the light bulb will flash in the rhythm of RPM1 - RPM2.

  In the end, we managed to produce a 1 Hz oscillation started from 2 motors at about 2000 RPM.

  Same technique as used in telecommunication for frequency shifting, frequency modulation, software define radios, etc., but applied to an incandescent light bulb with the help of 2 reed switches.
  

• Crazy light bulb flashing by itself

  RoGeorge • 08/01/2017 at 01:05 • 0 comments

  This video was made mainly to learn how to make and edit a video with Blender.
  

  Also, it was quite a surprise to find such a rare type of light bulb in one of my own junk boxes. I didn't knew such a thing even exists, never mind that I was having one.
  

• Phew, what a day!

  RoGeorge • 08/01/2017 at 00:56 • 0 comments

  F*ck me!

  Just learned today Blender and Gimp, bad enough to make my first (edited) video. Assembled the project, made the shooting setup and filmed the raw footage. Also, made an account and figure out how to twitter (still not sure if I actually sent the tweet :o), in order to submit the videos to the "Flashing Light Prize 2017" contest. The last tweet was literally sent in the last minute. YouTube was nice enough and finished the second upload 2 minutes before the contest deadline, so it left me a full minute to send the tweet.

  Making videos is tedious!

  First one was made mainly to learn video editing, but I wasn't paying attention to the clock, and after I finished it, I realized there is no time for the second video, which was supposed to be the interesting one, so I made a kind of draft and published it anyway.

  Phew, what a day!

  :o)

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